From CAT-like to POD-like Enzymatic Activity of Cu-BHT Tuning by Substrate Engineering

Abstract

Abstract: Two-dimensional metal-organic framework Cu-BHT is a highly promising nanozyme, yet the mechanisms regulating its type of enzyme-like activity remain unclear. This study employs density functional theory (DFT) calculations to reveal the decisive role of a SiO2 substrate in modulating the decomposition pathway and activity of hydrogen peroxide (H2O2) catalyzed by Cu-BHT. The calculation results demonstrate that free-standing Cu-BHT exhibits excellent CAT-like activity, with a highly exothermic reaction energy of -1.893 eV for the decomposition of H2O2 into H2O and O2. However, upon introducing a SiO2 substrate, interfacial charge redistribution markedly alters the reaction thermodynamics, resulting in a POD-like activity of the Cu-BHT. The pathway for catalytically decomposing H2O2 to produce reactive hydroxyl radicals (OH*) becomes more favorable, with a reaction energy of -0.498 eV. This discovery provides the atomic-level insight into how substrate engineering can switch the enzyme-mimicking activity of Cu-BHT, offering a crucial theoretical foundation for the rational design of functionalized smart nanozymes by tailoring the interfacial microenvironment.